<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <ul>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
    </ul>
</body>
<style>
    *{
        padding: 0;
        margin: 0;
    }
    body{
        display: flex;
        justify-content: center;
        align-items: center;
        height: 100vh;
        background-color: #000;
    }
    ul{
        position: relative;
        display: flex;
        height: 200px;
    }
    ul::after{
        content: '爱心怦怦跳';
        position: absolute;
        top: 0;
        left: 50%;
        color: aquamarine;
        font-size: 30px;
        font-weight: 700;
        transform: translate(-50%,-700%);
    }

    ul li{
        width: 20px;
        height: 20px;
        border-radius: 10px;
        margin: 0 10px;
    }

    li:nth-child(1){
        /* background: linear-gradient(90deg,red,orange); */
        background-color: red;
        animation: love1 5s 0s infinite;
    }
    li:nth-child(2){
        background-color: rgb(228, 87, 22);
        animation: love2 5s 0.2s infinite;
    }
    li:nth-child(3){
        background-color: rgb(255, 174, 0);
        animation: love3 5s 0.4s infinite;
    }
    li:nth-child(4){
        background-color: rgb(238, 255, 0);
        animation: love4 5s 0.6s infinite;
    }
    li:nth-child(5){
        background-color: rgb(157, 255, 0);
        animation: love5 5s 0.8s infinite;
    }
    li:nth-child(6){
        background-color: rgb(9, 255, 0);
        animation: love4 5s 1s infinite;
    }
    li:nth-child(7){
        background-color: rgb(0, 255, 128);
        animation: love3 5s 1.2s infinite;
    }
    li:nth-child(8){
        background-color: rgb(0, 255, 221);
        animation: love2 5s 1.4s infinite;
    }
    li:nth-child(9){
        background-color: rgb(0, 183, 255);
        animation: love1 5s 1.6s infinite;
    }

    @keyframes love1{
        30%,50%{
            height: 60px;
            transform: translateY(-30px);
        }
        70%,100%{
            height: 20px;
            transform: translateY(0);
        }
    }
    @keyframes love2{
        30%,50%{
            height: 125px;
            transform: translateY(-60px);
        }
        70%,100%{
            height: 20px;
            transform: translateY(0);
        }
    }
    @keyframes love3{
        30%,50%{
            height: 160px;
            transform: translateY(-75px);
        }
        70%,100%{
            height: 20px;
            transform: translateY(0);
        }
    }
    @keyframes love4{
        30%,50%{
            height: 180px;
            transform: translateY(-60px);
        }
        70%,100%{
            height: 20px;
            transform: translateY(0);
        }
    }
    @keyframes love5{
        30%,50%{
            height: 200px;
            transform: translateY(-45px);
        }
        70%,100%{
            height: 20px;
            transform: translateY(0);
        }
    }
</style>
</html>